The present embodiments relate to ultrasound transducers. In particular, the present embodiments relate to a reconfigurable transducer array.
One-dimensional transducers are used to scan a plane with electronic steering. For scanning a volume, a two-dimensional transducer may be used. However, the number of beamforming channels greatly increases for scanning with a two-dimensional transducer. Many ultrasound imaging systems do not have sufficient channels. An alternative is a mechanically rotated one-dimensional transducer (i.e., a wobbler). However, the mechanical motion may be insufficiently rapid for real-time volume scanning.
A multi-dimensional transducer array may be used with electronic switching to both provide for volume scanning and a fewer number of required beamformer channels. U.S. Pat. No. 6,676,602 describes such embodiments. For example, an electronically rotated array is an array of elements where the aperture used during scanning is electronically controlled. Switches connect different elements to different beamformer channels, allowing rotation of the aperture for sequential scanning. For example, a one-dimensional aperture is rotated electronically on the face of a two-dimensional transducer array. By controlling the configuration of the switches, the one-dimensional array may be oriented to any rotational angle. Within a given aperture, the defined one-dimensional array may steer scan lines. For volume scanning, the volume is sampled by collecting a series of azimuth-spaced beam groups at each rotation angle.
The switching to allow beamformation in real-time volume scanning may require high performance switches. For interconnecting a plurality of elements, the switches should have low “on” resistance. Isolation in the “off” state helps with beam formation. The size of the switch is also important since the switches may be placed within a small probe for operating with thousands of acoustic elements. Conventional switching approaches suffer from issues such as 1/f noise, crosstalk, impractical DC power, die size, or parasitic capacitance.